A position detection device having a pen-type position indicator for detecting a position by moving the pen on a position detection plane is called a digitizer, and is widely spread as an input device for computers. The position detection device includes a position detection flat plate, and a circuit board (sensor board) disposed therebelow and having loop coils formed on the surface of the board. Then, the position of the position indicator is detected by using electromagnetic induction generated by the position indicator and the loop coils.
As referred to in Patent Document 1, for example, a shield plate made of nickel chromium alloy is attached to a face opposite to the face of the position detection plane of the sensor board in a position detection device via an adhesive layer for efficient communication by controlling the magnetic flux generated at the time of electromagnetic induction.
Meanwhile, Patent Document 2 has proposed, for example, a composite magnetic sheet having flexibility formed by blending a soft magnetic powder shaped flat and a binder as a composite magnetic sheet disposed on the back face of an antenna in the data carrier and the reader-writer in an automatic recognition device transmitting and receiving data by electromagnetic waves.